Indole-3-Carbinol: a Plant Hormone Combatting Cancer[Version 1; Peer

F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

REVIEW Indole-3-carbinol: a plant hormone combatting cancer [version 1; peer review: 2 approved] Ella Katz1,2, Sophia Nisani1, Daniel A. Chamovitz 1

1School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel 2Department of Plant Sciences, University of California , Davis , USA

First published: 01 Jun 2018, 7(F1000 Faculty Rev):689 ( Open Peer Review v1 https://doi.org/10.12688/f1000research.14127.1) Latest published: 01 Jun 2018, 7(F1000 Faculty Rev):689 ( https://doi.org/10.12688/f1000research.14127.1) Reviewer Status

Abstract Invited Reviewers A diet rich in cruciferous vegetables such as cauliflower, broccoli, and 1 2 cabbage has long been considered healthy, and various epidemiological studies suggest that the consumption of cruciferous vegetables contributes version 1 to a cancer-protecting diet. While these vegetables contain a vast array of published phytochemicals, the mechanism by which these vegetables counteract 01 Jun 2018 cancer is still largely unresolved. Numerous in situ studies have implicated indole-3-carbinol, a breakdown product of the glucosinolate indole-3-ylmethylglucosinolate, as one of the phytochemicals with F1000 Faculty Reviews are written by members of anti-cancer properties. Indole-3-carbinol influences a range of cellular the prestigious F1000 Faculty. They are processes, but the mechanisms by which it acts on cancer cells are slowly commissioned and are peer reviewed before being revealed. Recent studies on the role of indole-3-carbinol in publication to ensure that the final, published version Arabidopsis opens the door for cross-kingdom comparisons that can help in understanding the roles of this important phytohormone in both plant is comprehensive and accessible. The reviewers biology and combatting cancer. who approved the final version are listed with their names and affiliations. Keywords glucosinolates, indole-3-carbinol, cancer prevention, cruciferous vegetables 1 Gary L. Firestone, University of California at Berkeley, Berkely, USA

2 Juan M. Zapata, CSIC-UAM, Madrid, Spain

Any comments on the article can be found at the end of the article.

Page 1 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

Corresponding author: Daniel A. Chamovitz ([email protected]) Author roles: Katz E: Conceptualization, Writing – Original Draft Preparation, Writing – Review & Editing; Nisani S: Investigation, Writing – Review & Editing; Chamovitz DA: Project Administration, Supervision, Writing – Original Draft Preparation, Writing – Review & Editing Competing interests: No competing interests were disclosed. Grant information: Our research into the role of I3C in Arabidopsis is funded by grants from the Binational Agricultural Research and Development Fund (BARD, IS450512R and US484615C). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Copyright: © 2018 Katz E et al. This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How to cite this article: Katz E, Nisani S and Chamovitz DA. Indole-3-carbinol: a plant hormone combatting cancer [version 1; peer review: 2 approved] F1000Research 2018, 7(F1000 Faculty Rev):689 (https://doi.org/10.12688/f1000research.14127.1) First published: 01 Jun 2018, 7(F1000 Faculty Rev):689 (https://doi.org/10.12688/f1000research.14127.1)

Page 2 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

Introduction glucosinolate breakdown products cause the characteristic sharp A diet rich in cruciferous vegetables such as cauliflower, taste of cruciferous vegetables and typically have a deterrent broccoli, and cabbage has long been considered healthy. Even effect on generalist herbivores10–12. in ancient times, extracts from these vegetables were thought to have medicinal and curative properties, and both Pythagoras and Breakdown of indole-3-ylmethylglucosinolate (I3M-GS), one of Hippocrates understood the medicinal properties of mustard the most widely distributed glucosinolates, leads to the forma- extracts1. In the 20th century, epidemiological studies pointing to tion of indole-3-acetonitrile (I3N) and indole-3-carbinol (I3C) the protective properties of cruciferous vegetables in a cancer- (Figure 1)13. I3C, in turn, can react with itself and a variety of other protecting diet started to accumulate2. A meta-analysis of studies plant metabolites to form conjugates, some of which are shown carried out over 18 years in Europe revealed an inverse associa- in Figure 1. Most of these I3C conjugates have as-yet-unknown tion between weekly consumption of cruciferous vegetables and functions in plant metabolism, though, interestingly, another several common cancers, including colorectal, breast, kidney, function of glucosinolate breakdown products may be to signal and upper digestive tract cancers3. While these vegetables contain further plant defense responses14. Therefore, it is possible that a vast array of phytochemicals4, the mechanism by which these I3M-GS breakdown also triggers other downstream responses in vegetables counteract cancer is still largely unresolved. Arabidopsis and other crucifers.

The anticarcinogenic properties associated with crucifers are From a dietary perspective, cooking vegetables affects their primarily attributed to the presence of glucosinolates, a family of profile of glucosinolate breakdown15. Boiling leads to inactivation secondary metabolites that are synthesized uniquely in this plant of the myrosinase enzyme but can also lead to a non-enzymatic family and play a dominant role in plant defenses against insects5. breakdown of I3M-GS to I3C and I3N16. In addition, human gut Glucosinolates are derived from glucose and amino acids and microbes can lead to glucosinolate breakdown17. contain various modifications to their side chain. The exact glu- cosinolate profile varies among crucifer species, and more than Indole-3-carbinol and cancer 140 glucosinolates have been characterized, including approxi- The glucosinolate breakdown products, rather than intact mately 40 in Arabidopsis6,7. Herbivory or other tissue damage glucosinolates, primarily contribute to the anticarcinogenic initiates the hydrolysis of glucosinolates by an endogenous plant effects of eating cabbage, broccoli, and related vegetables11,12,18. β-thioglucosidase termed “myrosinase”. Glucosinolates and I3C has long been studied regarding potential roles in cancer myrosinase are stored in separate plant compartments and meet management19,20, and many studies showed that I3C suppresses the only following cell rupture. This separation is likely an adapta- proliferation of various cancer cell lines, including breast, colon, tion to allow the targeted production of glucosinolate breakdown prostate, and endometrial cancer cells (reviewed in 19,21). One products, which are toxic to not only herbivores and pathogens example of its anti-proliferative properties comes from a study but also the plants themselves. Further catalysis and spontane- conducted on non-tumorigenic and tumorigenic breast epithelial ous degradation results in the formation of nitriles, epithionitriles, cells (MCF10A and MCF10CA1a, respectively), which showed oxazolidine-2-thiones, thiocyanates, and isothiocyanates8,9. These that I3C induced apoptosis in the breast cancer cells but not in

Figure 1. Myrosinase-catalyzed breakdown of indol-3-ylmethylglucosinolate (I3M-GS). Myrosinase-catalyzed breakdown of I3M-GS leads to the formation of unstable intermediates and then to indole-3-acetonitrile (I3N) and indole-3-carbionol (I3C). I3C reacts with itself and other plant metabolites to form a number of conjugates, some of which are shown.

Page 3 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

the non-tumorigenic breast epithelial cells22. I3C and one of its available genetic and genomic resources make Arabidopsis an reaction products, diindolylmethane (DIM), were implicated in excellent model system not only for plant biology but also for the induction of phase 1 detoxification enzymes, which can result eukaryotic research in general52. in the breakdown of other dietary carcinogens. Both in situ and in vivo studies point to a role for I3C as a chemoprotective agent in While the role of I3C in deterring herbivores is well studied53, breast and prostate cancer23. as is the biochemical pathway leading to the production of I3C13, the secondary responses in plants induced by I3C are only now The exact mechanisms by which I3C influences human cells starting to be revealed. Our recent studies highlight that I3C is are unclear, though direct interaction with a variety of signaling not only a defensive chemical targeting herbivores but also a pathways has been proposed. The treatment of various cancer cells signaling molecule modulating different cellular and developmen- with I3C induces G1 cell cycle arrest24–30. Other studies pointed tal pathways. to a connection between treatment of I3C and stimulation of apoptosis in several tumor cells25,31–34. I3C also induced autophagy Using Arabidopsis as a model system, we showed that exogenously in different cell lines. For example, the treatment of human colon applied I3C rapidly and reversibly inhibited root elongation in a cancer HT-29 cells with I3C and genistin induced autophagy and dose-dependent manner54. This inhibition was accompanied by suppressed the cells’ viability35. The treatment of human breast three I3C-induced responses that are relevant for our understanding cancer cell lines with a cyclic tetrameric derivative of I3C resulted of I3C activity in inhibiting cancer. in upregulation of key signaling molecules involved in endo- plasmic reticulum stress response and autophagy36. I3C also has First, the application of I3C led to a cessation of cell division the potential to modulate the metabolism of estrogen, and, through in the root meristem (Figure 2A). While normally a number of this, it may lower the risk of hormone-dependent cancers37–39. CycB1-expressing cells are visible in the root meristem, follow- In addition, I3C inhibited tumor invasion and metastasis40–44 ing I3C treatment, no CycB1-containing cells were detected, indi- and modulated the activity of several transcription factors and cating a cessation of cell division. This conclusion is supported various protein kinases21. Interestingly, I3C may also be involved by transcript-profiling results showing the downregulation of cell in the inhibition of amyloid fibril formation45. I3C was proposed cycle genes six hours following exposure to I3C55. to act as an angiogenesis agent, as it was shown to inhibit the 46 development of new blood vessels . A number of studies have Fluorescence-activated cell sorting (FACS) analysis on nuclei shown that I3C treatment leads to various changes in gene isolated from root tips further indicates a stoppage of the cell expression, including changes in key microRNAs (reviewed cycle. As seen in Figure 2B, three distinct populations of nuclei in 47). The complex mixture of indole metabolites found in cru- are detected in untreated roots, corresponding to 2n, 4n, and 8n ciferous vegetables likely has synergistic anticarcinogenic effects nuclei. However, following treatment with I3C, there is a progres- 32 that are not seen in experiments with individual compounds . sive loss of the 4n and 8n populations, with a concurrent increase in cells with increased side-scatter (population B). In vivo studies showed that I3C inhibits the development of different cancers in several animals when given before or in Second, the application of I3C led to a loss of auxin (indole-3- parallel to a carcinogen. However, when I3C was given to the acetic acid [IAA]) activity in the root meristem54. Auxin is the animals after the carcinogen, I3C promoted carcinogenesis48. most central plant hormone, controlling nearly all aspects of This concern regarding the long-term effects of I3C treatment on plant growth and development56. I3C affects plant growth and cancer risk in humans resulted in some caution in the use of I3C development by directly modulating auxin signaling. I3C as a dietary supplement in cancer management protocols49,50. antagonized a number of auxin-induced growth phenotypes, including inhibition of root elongation, formation of root Mammalian cellular processes attributed to I3C action are hairs, and secondary root branching. I3C directly interferes as diverse as the different phenotypes presented by the many with the auxin-dependent binding of the auxin-receptor Trans- cancers studied. Indeed, focusing on the effects of I3C on one port Inhibitor Response (TIR1) to two of its substrates54. The type of cancer (e.g. breast cancer) may present pleiotropic effects TIR1 auxin receptor is an F-box-containing subunit of the for I3C on multiple molecular targets (reviewed in 51) that may SCF (Skp, Cullin, F-box) E3 ubiquitin ligase complex. Auxin be distinct from those presented in another cancer type. While binding to the SCFTIR1/AFB promotes the degradation of auxin/ not often considered, to get a different perspective on the action indole-3-acetic acid (Aux/IAA) transcriptional repressors and of I3C in cells in general, it may be instructive to learn from through this regulates the transcription of the auxin-induced the activity of I3C in plants. genes57. I3C inhibits the auxin-dependent dimerization of the receptor with its substrates by competing with auxin for Indole-3-carbinol and plants the same binding site in TIR1. The model plant Arabidopsis thaliana provides an excellent system for elucidating the molecular mechanisms involved in I3C The third I3C-induced response relevant for our understanding action, as 1) it produces I3C endogenously following herbivory, of I3C activity in inhibiting cancer is autophagy. Exposure of 2) small amounts of I3C are produced constitutively in the roots, Arabidopsis roots to I3C leads to the induction of autophagy58. hinting at an endogenous role in maintaining homeostasis, and This autophagy is not general, aimed at bulk degradation of 3) its short life cycle and small stature coupled with advanced general cytoplasmic content for recycling, such as that occuring

Page 4 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

Figure 2. Indole-3-carbionol (I3C) affects cell cycle and nuclear complexity in the Arabidopsis root meristem. A. Confocal imaging reveals a lack of Cyclin B–GFP-expressing cells following I3C treatment. Seedlings expressing Cyclin B–GFP were grown on Murashige and Skoog (MS) medium for 4 days, treated with MS (left panel) or 500 μm I3C (right panel) for 6 hours, and imaged using confocal microscopy. Cell walls were stained using propidium iodide. B. Fluorescence-activated cell sorting (FACS) analysis reveals changes in nuclear complexity following I3C treatment. Nuclei were isolated from Arabidopsis roots treated with MS or MS plus I3C for the marked times between 0 and 15 hours and analyzed by FACS for DNA content (FL2-A = propidium iodide fluorescence) and nuclear complexity (SCC-H = light side scatter). The green, purple, and blue boxes represent the populations differing according to nuclear content, 2n, 4n, and the endoreplication population (8n), respectively. The red boxes represent two populations of nuclei (“A” and “B”) that differ according to side scatter.

under starvation conditions, but rather specific. Specific autophagy Although I3C-induced autophagy was detected in both plants and targets damaged proteins and other cellular components for animals, the direct signaling mechanism has yet to be elucidated. degradation59 and is seen in the co-localization of the GFP- However, this might hint at a shared signaling mechanism for AtATG8A and mCherry-AtNBR1 marker proteins in autophago- both plants and humans. Thus, not only is it instructive for cancer somes following I3C treatment. The I3C-induced autophagy biologists to learn from the activity of I3C in plants but also plant targets the TIR1 auxin receptor, thus connecting I3C-dependent biologists have much to gain from a closer understanding of the inhibition of auxin signaling55 and the I3C induction of mechanistic studies of cancer biologists. autophagy58. To date, only a few I3C-binding proteins have been identified. These two I3C-dependent processes were detected in roots not In human cells, the enzyme elastase, which mediates the con- only after direct exposure to exogenously applied I3C but also version of cyclin E from a higher- to a lower-molecular-weight following the treatment of leaves with I3C. Most importantly, form associated with cancer cell proliferation, was the first leaf-wounding also induced autophagy and inhibited the auxin identified specific target protein for63 I3C . I3C treatments also response in the root, and this effect of wounding was lost in inhibited elastase-dependent cleavage of an additional substrate, glucosinolate-defective mutants. This indicates that an I3C- membrane-associated CD40, a member of the tumor necrosis dependent signal is transported from leaves to the root meristem factor (TNF) receptor superfamily64. Thus, the I3C–elastase where auxin signaling is inhibited and autophagy is induced. nexus may aid in the development of targeted therapies of human Thus, I3C is not only a defensive metabolite that repels insects breast cancers where high elastase levels are correlated with but also involved in long-distance communication regulating poor prognosis. growth and development in plants. The only I3C-binding protein identified in plants to date is the Indole-3-carbinol, autophagy, and protein turnover TIR1 F-box protein. While auxin is a plant-specific hormone, The connection between I3C and autophagy is quite interesting, SCF complexes also exist in mammals and play important roles as this connection was also found in several human cancer in many mammalian functions65. TIR1 is related to the human cells, as described earlier35,36. The process of autophagy involves protein SKP266, so conceivably I3C could regulate protein the degradation of unnecessary or dysfunctional cellular turnover in mammals as well. This conjecture is supported by components through the actions of lysosomes (in mammals) or studies which showed that I3C targets and inhibits a different vacuoles (in plants). This process is evolutionarily conserved E3 ubiquitin ligase, NEDD4-1 (Neural precursor cell Expressed among eukaryotes, and its mechanism is well elucidated60,61. In Developmentally Down regulated gene 4-1) in human melanoma the context of cancer, autophagy can be viewed as a “double- cells67,68. Thus, an I3C-bound, inhibited NEDD4 would need to edged sword”. The activation of autophagy may function as a be cleared from the cell, and conceivably this could occur via tumor suppressor (by degrading the defective organelles and specific autophagy, just as I3C-bound, inhibited TIR1 is targeted cellular component) or can be exploited by the cancer cells to in plant roots for clearing by specific autophagy. As NEDD4 is generate nutrients and energy during periods of starvation62. frequently overexpressed in different types of human cancers69,

Page 5 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

I3C could be a potential therapeutic agent inhibiting the activity hormone-binding proteins71–75. Thus, the study of I3C in plants of the over-accumulated E3 ligase. can have direct implications for further understanding the role of I3C and perhaps controlling cancer in humans. While plants do not develop metastatic cancer as mammals do, plants can develop tumors. Plants and animals share numerous pathways and signaling cascades70, and approximately 70% of Competing interests the genes implicated in cancer have homologs in the Arabidopsis The authors declare that they have no competing interests. thaliana genome, similar to the percentages of human cancer genes in other established systems such as Drosophila melanogaster, Grant information Caenorhabditis elegans, and Saccharomyces cerevisiae52. Fur- Our research into the role of I3C in Arabidopsis is funded by grants thermore, while plants and animals obviously have independent from the Binational Agricultural Research and Development Fund hormonal regulatory mechanisms, some similarity and cross (BARD, IS-4505-12R and US-4846-15C). reactivity exists between the kingdoms. Plants produce phyto- estrogens and other steroid hormones, which also affect human The funders had no role in study design, data collection and analysis, hormone signaling, as well as a number of putative steroid decision to publish, or preparation of the manuscript.

References F1000 recommended

1. Fenwick GR, Heaney RK: Glucosinolates and their breakdown products in 16. Campbell LD, Slominski BA: Extent of thermal decomposition of indole cruciferous crops, foods and feedingstuffs. Food Chem. 1983; 11(4): 249–71. glucosinolates during the processing of canola seed. J Am Oil Chem Soc. 1990; Publisher Full Text 67(2): 73–5. 2. Verhoeven DT, Goldbohm RA, van Poppel G, et al.: Epidemiological studies on Publisher Full Text brassica vegetables and cancer risk. Cancer Epidemiol Biomarkers Prev. 1996; 17. Shapiro TA, Fahey JW, Wade KL, et al.: Human metabolism and excretion of 5(9): 733–48. cancer chemoprotective glucosinolates and isothiocyanates of cruciferous PubMed Abstract vegetables. Cancer Epidemiol Biomarkers Prev. 1998; 7(12): 1091–100. 3. Bosetti C, Filomeno M, Riso P, et al.: Cruciferous vegetables and cancer risk in a PubMed Abstract network of case-control studies. Ann Oncol. 2012; 23(8): 2198–203. 18. Bones AM, Rossiter JT: The myrosinase-glucosinolate system, its organisation PubMed Abstract | Publisher Full Text and biochemistry. Physiol Plant. 1996; 97(1): 194–208. 4. Björkman M, Klingen I, Birch AN, et al.: Phytochemicals of Brassicaceae in Publisher Full Text plant protection and human health--influences of climate, environment and 19. Fujioka N, Fritz V, Upadhyaya P, et al.: Research on cruciferous vegetables, agronomic practice. Phytochemistry. 2011; 72(7): 538–56. indole-3-carbinol, and cancer prevention: A tribute to Lee W. Wattenberg. Mol PubMed Abstract | Publisher Full Text Nutr Food Res. 2016; 60(6): 1228–38. 5. Fahey JW, Zalcmann AT, Talalay P: The chemical diversity and distribution of PubMed Abstract | Publisher Full Text | F1000 Recommendation glucosinolates and isothiocyanates among plants. Phytochemistry. 2001; 56(1): 20. Verhoeven DT, Verhagen H, Goldbohm RA, et al.: A review of mechanisms 5–51. underlying anticarcinogenicity by brassica vegetables. Chem Biol Interact. PubMed Abstract | Publisher Full Text 1997; 103(2): 79–129. 6. Kliebenstein DJ, Kroymann J, Brown P, et al.: Genetic control of natural PubMed Abstract | Publisher Full Text variation in Arabidopsis glucosinolate accumulation. Plant Physiol. 2001; 21. Aggarwal BB, Ichikawa H: Molecular targets and anticancer potential of indole- 126(2): 811–25. 3-carbinol and its derivatives. Cell Cycle. 2005; 4(9): 1201–15. PubMed Abstract | Publisher Full Text | Free Full Text | F1000 Recommendation PubMed Abstract | Publisher Full Text 7. Reichelt M, Brown PD, Schneider B, et al.: Benzoic acid glucosinolate esters and 22. Rahman KM, Aranha O, Sarkar FH: Indole-3-carbinol (I3C) induces apoptosis other glucosinolates from Arabidopsis thaliana. Phytochemistry. 2002; 59(6): 663–71. in tumorigenic but not in nontumorigenic breast epithelial cells. Nutr Cancer. PubMed Abstract | Publisher Full Text 2003; 45(1): 101–12. 8. Halkier BA, Gershenzon J: Biology and biochemistry of glucosinolates. Annu PubMed Abstract | Publisher Full Text Rev Plant Biol. 2006; 57: 303–33. 23. Bradlow HL: Review. Indole-3-carbinol as a chemoprotective agent in breast PubMed Abstract | Publisher Full Text and prostate cancer. In Vivo. 2008; 22(4): 441–5. 9. Sønderby IE, Geu-Flores F, Halkier BA: Biosynthesis of glucosinolates--gene PubMed Abstract discovery and beyond. Trends Plant Sci. 2010; 15(5): 283–90. 24. Cover CM, Hsieh SJ, Tran SH, et al.: Indole-3-carbinol inhibits the expression of PubMed Abstract | Publisher Full Text cyclin-dependent kinase-6 and induces a G1 cell cycle arrest of human breast 10. Bones AM, Rossiter JT: The enzymic and chemically induced decomposition of cancer cells independent of estrogen receptor signaling. J Biol Chem. 1998; glucosinolates. Phytochemistry. 2006; 67(11): 1053–67. 273(7): 3838–47. PubMed Abstract | Publisher Full Text PubMed Abstract | Publisher Full Text 11. Keck AS, Finley JW: Cruciferous vegetables: cancer protective mechanisms of 25. Chinni SR, Li Y, Upadhyay S, et al.: Indole-3-carbinol (I3C) induced cell growth glucosinolate hydrolysis products and selenium. Integr Cancer Ther. 2004; 3(1): inhibition, G1 cell cycle arrest and apoptosis in prostate cancer cells. 5–12. Oncogene. 2001; 20(23): 2927–36. PubMed Abstract | Publisher Full Text PubMed Abstract | Publisher Full Text 12. Kim YS, Milner JA: Targets for indole-3-carbinol in cancer prevention. J Nutr 26. Brandi G, Paiardini M, Cervasi B, et al.: A new indole-3-carbinol tetrameric Biochem. 2005; 16(2): 65–73. derivative inhibits cyclin-dependent kinase 6 expression, and induces G1 cell PubMed Abstract | Publisher Full Text cycle arrest in both estrogen-dependent and estrogen-independent breast 13. Agerbirk N, De Vos M, Kim JH, et al.: Indole glucosinolate breakdown and its cancer cell lines. Cancer Res. 2003; 63(14): 4028–36. biological effects. Phytochem Rev. 2009; 8: 101–20. PubMed Abstract Publisher Full Text 27. Zhang J, Hsu B A JC, Kinseth B A MA, et al.: Indole-3-carbinol induces a G1 cell cycle arrest and inhibits prostate-specific antigen production in human LNCaP 14. Clay NK, Adio AM, Denoux C, et al.: Glucosinolate metabolites required for prostate carcinoma cells. Cancer. 2003; 98(11): 2511–20. an Arabidopsis innate immune response. Science. 2009; 323(5910): 95–101. PubMed Abstract | Publisher Full Text PubMed Abstract Publisher Full Text Free Full Text F1000 Recommendation | | | 28. Cover CM, Hsieh SJ, Cram EJ, et al.: Indole-3-carbinol and tamoxifen cooperate 15. Palermo M, Pellegrini N, Fogliano V: The effect of cooking on the to arrest the cell cycle of MCF-7 human breast cancer cells. Cancer Res. 1999; phytochemical content of vegetables. J Sci Food Agric. 2014; 94(6): 1057–70. 59(6): 1244–51. PubMed Abstract | Publisher Full Text | F1000 Recommendation PubMed Abstract

Page 6 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

29. Matsuzaki Y, Koyama M, Hitomi T, et al.: Indole-3-carbinol activates the cyclin- 50. Lee BM, Park K: Beneficial and adverse effects of chemopreventive agents. dependent kinase inhibitor p15INK4b gene. FEBS Lett. 2004; 576(1–2): 137–40. Mutat Res. 2003; 523–524: 265–78. PubMed Abstract | Publisher Full Text PubMed Abstract | Publisher Full Text 30. Chen Z, Tao ZZ, Chen SM, et al.: Indole-3-carbinol inhibits nasopharyngeal 51. Weng JR, Tsai CH, Kulp SK, et al.: Indole-3-carbinol as a chemopreventive and carcinoma growth through cell cycle arrest in vivo and in vitro. PLoS One. 2013; anti-cancer agent. Cancer Lett. 2008; 262(2): 153–63. 8(12): e82288. PubMed Abstract | Publisher Full Text | Free Full Text PubMed Abstract | Publisher Full Text | Free Full Text 52. Jones AM, Chory J, Dangl JL, et al.: The impact of Arabidopsis on human health: 31. Ge X, Fares FA, Yannai S: Induction of apoptosis in MCF-7 cells by indole-3- diversifying our portfolio. Cell. 2008; 133(6): 939–43. carbinol is independent of p53 and bax. Anticancer Res. 1999; 19(4B): 3199–203. PubMed Abstract | Publisher Full Text | Free Full Text PubMed Abstract 53. Kim JH, Lee BW, Schroeder FC, et al.: Identification of indole glucosinolate 32. Bonnesen C, Eggleston IM, Hayes JD: Dietary indoles and isothiocyanates that breakdown products with antifeedant effects on Myzus persicae (green peach are generated from cruciferous vegetables can both stimulate apoptosis and aphid). Plant J. 2008; 54(6): 1015–26. confer protection against DNA damage in human colon cell lines. Cancer Res. PubMed Abstract | Publisher Full Text 2001; 61(16): 6120–30. 54. Katz E, Nisani S, Yadav BS, et al.: The glucosinolate breakdown product indole- PubMed Abstract 3-carbinol acts as an auxin antagonist in roots of Arabidopsis thaliana. Plant J. 33. Safa M, Jafari L, Alikarami F, et al.: Indole-3-carbinol induces apoptosis of 2015; 82(4): 547–55. chronic myelogenous leukemia cells through suppression of STAT5 and Akt PubMed Abstract | Publisher Full Text signaling pathways. Tumour Biol. 2017; 39(6): 1010428317705768. 55. Katz E, Nisani S, Sela M, et al.: The effect of indole-3-carbinol on PIN1 and PIN2 PubMed Abstract | Publisher Full Text | F1000 Recommendation in Arabidopsis roots. Plant Signal Behav. 2015; 10(9): e1062200. PubMed Abstract | Publisher Full Text | Free Full Text 34. Perez-Chacon G, de Los Rios C, Zapata JM: Indole-3-carbinol induces cMYC 56. Zažímalová E, Petrášek J, Benková E: Auxin and Its Role in Plant Development. and IAP-family downmodulation and promotes apoptosis of Epstein-Barr Vienna: Springer Vienna; 2014. virus (EBV)-positive but not of EBV-negative Burkitt’s lymphoma cell lines. Publisher Full Text Pharmacol Res. 2014; 89: 46–56. PubMed Abstract | Publisher Full Text | F1000 Recommendation 57. Dharmasiri N, Dharmasiri S, Estelle M: The F-box protein TIR1 is an auxin 35. Nakamura Y, Yogosawa S, Izutani Y, et al.: A combination of indol-3-carbinol receptor. Nature. 2005; 435(7041): 441–5. and genistein synergistically induces apoptosis in human colon cancer HT-29 PubMed Abstract | Publisher Full Text | F1000 Recommendation cells by inhibiting Akt phosphorylation and progression of autophagy. Mol 58. Katz E, Chamovitz DA: Wounding of Arabidopsis leaves induces indole-3- Cancer. 2009; 8: 100. carbinol-dependent autophagy in roots of Arabidopsis thaliana. Plant J. 2017; PubMed Abstract | Publisher Full Text | Free Full Text 91(5): 779–87. 36. Galluzzi L, De Santi M, Crinelli R, et al.: Induction of endoplasmic reticulum PubMed Abstract | Publisher Full Text stress response by the indole-3-carbinol cyclic tetrameric derivative CTet in 59. Svenning S, Lamark T, Krause K, et al.: Plant NBR1 is a selective autophagy human breast cancer cell lines. PLoS One. 2012; 7(8): e43249. substrate and a functional hybrid of the mammalian autophagic adapters PubMed Abstract | Publisher Full Text | Free Full Text NBR1 and p62/SQSTM1. Autophagy. 2011; 7(9): 993–1010. 37. Telang NT, Katdare M, Bradlow HL, et al.: Inhibition of proliferation and PubMed Abstract | Publisher Full Text | Free Full Text modulation of estradiol metabolism: novel mechanisms for breast cancer 60. Yang Z, Klionsky DJ: Mammalian autophagy: core molecular machinery and prevention by the phytochemical indole-3-carbinol. Proc Soc Exp Biol Med. signaling regulation. Curr Opin Cell Biol. 2010; 22(2): 124–31. 1997; 216(2): 246–52. PubMed Abstract | Publisher Full Text | Free Full Text PubMed Abstract | Publisher Full Text 61. Michaeli S, Galili G, Genschik P, et al.: Autophagy in Plants--What’s New on 38. Meng Q, Yuan F, Goldberg ID, et al.: Indole-3-carbinol is a negative regulator of the Menu? Trends Plant Sci. 2016; 21(2): 134–44. estrogen receptor-alpha signaling in human tumor cells. J Nutr. 2000; 130(12): PubMed Abstract Publisher Full Text F1000 Recommendation 2927–31. | | PubMed Abstract | Publisher Full Text 62. Carew JS, Kelly KR, Nawrocki ST: Autophagy as a target for cancer therapy: new developments. Cancer Manag Res. 2012; 4: 357–65. 39. Riby JE, Feng C, Chang YC, et al.: The major cyclic trimeric product of indole- PubMed Abstract Publisher Full Text Free Full Text 3-carbinol is a strong agonist of the estrogen receptor signaling pathway. | | Biochemistry. 2000; 39(5): 910–8. 63. Nguyen HH, Aronchik I, Brar GA, et al.: The dietary phytochemical indole-3- PubMed Abstract | Publisher Full Text carbinol is a natural elastase enzymatic inhibitor that disrupts cyclin E protein processing. Proc Natl Acad Sci U S A. 2008; 105(50): 19750–5. 40. Meng Q, Goldberg ID, Rosen EM, et al.: Inhibitory effects of Indole-3-carbinol on PubMed Abstract Publisher Full Text Free Full Text invasion and migration in human breast cancer cells. Breast Cancer Res Treat. | | 2000; 63(2): 147–52. 64. Aronchik I, Bjeldanes LF, Firestone GL: Direct inhibition of elastase activity PubMed Abstract | Publisher Full Text by indole-3-carbinol triggers a CD40-TRAF regulatory cascade that disrupts NF-kappaB transcriptional activity in human breast cancer cells. Cancer Res. 41. Meng Q, Qi M, Chen DZ, et al.: Suppression of breast cancer invasion and 2010; 70(12): 4961–71. migration by indole-3-carbinol: associated with up-regulation of BRCA1 and PubMed Abstract Publisher Full Text E-cadherin/catenin complexes. J Mol Med (Berl). 2000; 78(3): 155–65. | PubMed Abstract | Publisher Full Text 65. Cardozo T, Pagano M: The SCF ubiquitin ligase: insights into a molecular machine. Nat Rev Mol Cell Biol. 2004; 5(9): 739–51. 42. Firestone GL, Bjeldanes LF: Indole-3-carbinol and 3-3’-diindolylmethane PubMed Abstract Publisher Full Text antiproliferative signaling pathways control cell-cycle gene transcription in | human breast cancer cells by regulating promoter-Sp1 transcription factor 66. Ruegger M, Dewey E, Gray WM, et al.: The TIR1 protein of Arabidopsis functions interactions. J Nutr. 2003; 133(7 Suppl): 2448S–55. in auxin response and is related to human SKP2 and yeast grr1p. Genes Dev. PubMed Abstract | Publisher Full Text 1998; 12(2): 198–207. PubMed Abstract Publisher Full Text Free Full Text 43. Sarkar FH, Li Y: Indole-3-carbinol and prostate cancer. J Nutr. 2004; | | 134(12 Suppl): 3493S–8. 67. Aronchik I, Kundu A, Quirit JG, et al.: The antiproliferative response of PubMed Abstract | Publisher Full Text indole-3-carbinol in human melanoma cells is triggered by an interaction with 44. Fan S, Meng Q, Auborn K, et al.: BRCA1 and BRCA2 as molecular targets for NEDD4-1 and disruption of wild-type PTEN degradation. Mol Cancer Res. 2014; phytochemicals indole-3-carbinol and genistein in breast and prostate cancer 12(11): 1621–34. cells. Br J Cancer. 2006; 94(3): 407–26. PubMed Abstract | Publisher Full Text | Free Full Text | F1000 Recommendation PubMed Abstract Publisher Full Text Free Full Text | | 68. Quirit JG, Lavrenov SN, Poindexter K, et al.: Indole-3-carbinol (I3C) 45. Cohen T, Frydman-Marom A, Rechter M, et al.: Inhibition of amyloid fibril analogues are potent small molecule inhibitors of NEDD4-1 ubiquitin formation and cytotoxicity by hydroxyindole derivatives. Biochemistry. 2006; ligase activity that disrupt proliferation of human melanoma cells. Biochem 45(15): 4727–35. Pharmacol. 2017; 127: 13–27. PubMed Abstract | Publisher Full Text PubMed Abstract | Publisher Full Text | F1000 Recommendation 46. Chang X, Tou JC, Hong C, et al.: 3,3’-Diindolylmethane inhibits angiogenesis and the growth of transplantable human breast carcinoma in athymic mice. 69. Ye X, Wang L, Shang B, et al.: NEDD4: a promising target for cancer Carcinogenesis. 2005; 26(4): 771–8. therapy. Curr Cancer Drug Targets. 2014; 14(6): 549–56. PubMed Abstract | Publisher Full Text PubMed Abstract | Publisher Full Text | Free Full Text | F1000 Recommendation 47. Phuah NH, Nagoor NH: Regulation of microRNAs by natural agents: new 70. Trapp O, Seeliger K, Puchta H: Homologs of breast cancer genes in plants. strategies in cancer therapies. Biomed Res Int. 2014; 2014: 804510. Front Plant Sci. 2011; 2: 19. PubMed Abstract | Publisher Full Text | Free Full Text PubMed Abstract | Publisher Full Text | Free Full Text 48. Higdon JV, Delage B, Williams DE, et al.: Cruciferous vegetables and human 71. Hsieh CJ, Hsu YL, Huang YF, et al.: Molecular Mechanisms of Anticancer cancer risk: epidemiologic evidence and mechanistic basis. Pharmacol Res. Effects of Phytoestrogens in Breast Cancer. Curr Protein Pept Sci. 2018; 19(3): 2007; 55(3): 224–36. 323–32. PubMed Abstract | Publisher Full Text | Free Full Text PubMed Abstract | Publisher Full Text | F1000 Recommendation 49. Dashwood RH: Indole-3-carbinol: anticarcinogen or tumor promoter in brassica 72. Vert G, Nemhauser JL, Geldner N, et al.: Molecular mechanisms of steroid vegetables? Chem Biol Interact. 1998; 110(1–2): 1–5. hormone signaling in plants. Annu Rev Cell Dev Biol. 2005; 21: 177–201. PubMed Abstract | Publisher Full Text PubMed Abstract | Publisher Full Text

Page 7 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

73. Vriet C, Russinova E, Reuzeau C: From squalene to brassinolide: the steroid Steroids. 2012; 77(3): 169–73. metabolic and signaling pathways across the plant kingdom. Mol Plant. 2013; PubMed Abstract | Publisher Full Text 6(6): 1738–57. 75. Yang XH, Xu ZH, Xue HW: Arabidopsis membrane steroid binding protein 1 is PubMed Abstract | Publisher Full Text involved in inhibition of cell elongation. Plant Cell. 2005; 17(1): 116–31. 74. Janeczko A: The presence and activity of progesterone in the plant kingdom. PubMed Abstract | Publisher Full Text | Free Full Text

Page 8 of 9 F1000Research 2018, 7(F1000 Faculty Rev):689 Last updated: 17 JUL 2019

Open Peer Review

Current Peer Review Status:

Editorial Note on the Review Process F1000 Faculty Reviews are written by members of the prestigious F1000 Faculty. They are commissioned and are peer reviewed before publication to ensure that the final, published version is comprehensive and accessible. The reviewers who approved the final version are listed with their names and affiliations.

The reviewers who approved this article are: Version 1

1 Juan M. Zapata Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Madrid, Spain Competing Interests: No competing interests were disclosed. 2 Gary L. Firestone Department of Molecular and Cell Biology and the Cancer Research Laboratory, University of California at Berkeley, Berkely, California, USA Competing Interests: No competing interests were disclosed.

The benefits of publishing with F1000Research:

Your article is published within days, with no editorial bias

You can publish traditional articles, null/negative results, case reports, data notes and more

The peer review process is transparent and collaborative

Your article is indexed in PubMed after passing peer review

Dedicated customer support at every stage

For pre-submission enquiries, contact [email protected]

Page 9 of 9